1. Field of the Invention
The present invention relates to carbon-carbon bond formation mediated by metal complexes that contain one or more chelating ligands. The complex can be used for catalyzing carbon-carbon bond formation between saturated and saturated, saturated and unsaturated, and unsaturated and unsaturated bonds.
2. Description of the Related Art
Metal complexes are commonly used as catalysts for unusual chemical transformation in chemical industry, petrochemical industry, pharmaceutical industry, lubricant material and polymer material. One remarkable example in this aspect is the chelating amido phosphine derivatives that contain the —SiMe2CH2— ligand backbone as depicted in formula i.

The tridentate ligands of this type have shown widespread reactivity with metals of the periodic table. These ligands, however, are prone to phosphine dissociation under certain circumstances due to the flexibility of the backbone. With the silyl linker, the ligands may become reactive, as cleavage of both N—Si and C—H bonds has been observed in the ligand depicted in formula i.
A ligand represented by the formula ii is disclosed in U.S. Pat. No. 6,395,916.

The amino group and phosphine groups are located in different phenyl group for stabling the linkage of the ligand by the electrons in the phenyl group.
A ligand represented by the formula iii is disclosed in U.S. Pat. No. 6,562,989,
wherein the metal ion is linked to the two different rings for stabling the linkage of the ligand by the electrons in the rings.
Furthermore, a ligand represented by the formula iv is disclosed in U.S. Pat. No. 6,573,345,
wherein the pyrrolyl group renders the linkage of the ligand stable. The ligand is mainly used for catalyzing olefin oligomerization and polymerization.